Core-taking apparatus



Oct. 17, 1961 w. JANSON ETAL 3,004,514

CORE-TAKING APPARATUS 3 Sheets-Sheet -1 Filed 001;. 20, 1958 Y m N E O 0 T N T S H R m N N W O E T M M W G Y Y 6 O R RR E A L H Y B Y a ,0) W v 2 Oct. 17, 1961 w. JANSON ETAL 3,004,614

CORE-TAKING APPARATUS Filed Oct. 20, 1958 5 Sheets-Sheet 3 INVENTORS.

LEROY W JANSON HARRY G. DeWITT LL %w%flm' ATTORNEY llnited rates Parent Q 3,l04,6l4 CGRETAKING APPARATUS Leroy W. Janson, Clarks Summit, and Harry G. De Witt,

Factoryville, Pan, assignors to Sprague 6k Henwood,

Incorporated, Scranton, Pa., a corporation of Pennsylvania Filed Oct. 20, 1958, Ser. No. 768,257 Claims. (fit. l75246) This invention relates to rotary core drilling apparatus employing a core barrel assembly comprising an outer, rotary barrel carrying the usual core bit, and an inner barrel which receives the core as it is being formed. Driven drill rod sections are coupled to the outer barrel.

In conventional core drilling, the core bit is advanced into the earth until a desired length of core has entered the innerbarrel of the core barrel assembly. Drilling is then stopped, and the entire assembly, viz., drill rod sections, outer barrel and bit, and inner barrel and core, is raised, the drill rod, which is usually in -foot sections, being uncoupled and stacked until the core barrel assembly is retracted to the surface. The core barrel assembly is then partially disassembled and the core removed.

In the core drilling apparatus of the present invention, the inner barrel of the core barrel assembly can be raised without the necessity of withdrawing the whole corebarrel assembly, the inner barrel being withdrawable axially through the outer barrel of the assembly and the drill rod sections by means of a wire cable, for example.

In addition to this general arrangement, the invention provides new and novel mechanism for limiting the axial movement of the inner barrel of the core barrel assembly into the outer barrel, and latching mechanism for latching the inner barrel of the core barrel assembly against rising during drilling, together with new and novel retrieving mechanism for unlatching the inner barrel, this mechanism at the same time attaching itself to the inner barrel, which along with the core can then be raised to the surface without the necessity of lifting or otherwise disturbing the bit, the outer barrel, and the drill rod sections.

The invention furthermore provides new and novel retrieving mechanism which, in addition to its retrieving function, is peculiarly adapted for lowering the inner core barrel into what is generally termed a dry hole.

In the accompanying drawings,

FIG. 1 is an elevational, exploded view showing rotary core drilling apparatus embodying the invention;

FIG. 2 is a part-sectional view of the apparatus of FIG. 1;

FIGS. 3, 4, 5, and 6 are sectional views taken substantially on the lines 3 3, 4-4, 5-5, and 6-6, respectively, of FIG. 2;

FIG. 7 is a fragmentary, sectional elevation showing the overshot or retrieving assembly in position to withdraw the inner barrel of the core barrel assembly;

FIG. 8 is a part-sectional elevation of the overshot assembly as it appears when lowering the inner barrel of the core barrel assembly into a dry hole;

FIG. 9 is a part-sectional elevation showing the inner barrel latched in position within the outer barrel and the overshot assembly in release position; and

MG. 10 is a section taken substantially on the line 10-14 of FIG. 9.

Referring to the drawings in detail and particularly, first of all, to FIGS. 1 to 6, inclusive, the embodiment of the invention therein illustrated comprises in general an outer core barrel "2, to the upper end of which the sectional drill rod 4 is thread-coupled. To the lower end of the outer barrel 2 a reaming shell 6 is thread-coupled, and thread-coupled 'to this shell is core bit 8. A diamond Patented Oct. 17, 1961 bit has been illustrated, but it is to be understood that any type of core bit conventionally employed in taking core samples may be used.

The inner barrel of the core barrel assembly comprises core-lifter case 10, which loosely extends into the drill bit 8 and is threaded onto inner-core-barrel extension or coupling section 12. 14 designates the core litter of the inner barrel. This lifter may comprise a resilient split steel ring having longitudinal slots or ribs adapted to grasp and hold the core sample, so as to break off the core sample and hold it within the inner barrel as the inner barrel is being raised. The inner-barrel extension or coupling section 12 is threaded onto the innerbarrel section 16.

Threaded into the upper end of the upper section 16 of the inner barrel is an elongated plug or cap 18. Extending axially of this plug 18 and projecting beyond the upper and lower ends thereof is a spindle 20. The lower or inner end of this spindle is provided with nut 22. The upper portion of the plug 18 is reduced in diameter to provide a neck 24, which extends into the lower end of inner-barrel head 26. Bearing bushing 28 is threaded into the head 26, and between head 30 of the spindle and the upper ends of neck 24 and bushing 28 is a ball bearing assembly 32. Set into the upper end of the inner-barrel head 26 is a fixed head pin 34.

It will be appreciated that the inner barrel of the core barrel assembly is adapted to be lowered and raised axially into and out of the outer barrel 2 and drill rod 4. It will be appreciated also that, by providing the ball bearing assembly 32, the outer barrel 2, bit 8, etc. can be rotated in normal fashion without imparting rotation to that part of the inner barrel of the core barrel assembly below the ball bearing assembly 32, thus protecting the core sample against damage.

It is quite apparent that some means must be provided to prevent rising or lifting of the inner-barrel assembly relative to the outer-bariel assembly and drill rod during drilling. This means takes the form of a plurality of latch fingers 36, integral or otherwise rigid with a ring or annulus 37, which is clamped between two adjacent finger-clamping sections 38 and 49 of the outer barrel 2. It is to be noted that the head 26 of the inner barrel is shouldered, as shown at 42, which shoulder engages the upper edge of latch finger ring 37, to limit the inward movement of the inner barrel and prevent lifter case 10 from contacting the bit 8.

FIG. 2 shows the inner-barrel assembly latched in place, the fingers 36 being thickened at their upper ends, as seen at 44, to provide shoulders which hook over and engagethe upper face of the inner-barrel head 26. This effectively and positively prevents upward movement of the inner-barrel assembly until the fingers 36 are sprung outwardly to disengage the face of the barrel head 26. To permit the fingers 36 to be sprung outwardly to unlatched position, the inner wall of the finger-clamping section 38 of the outer barrel is cut back, as seen at 46.

With the parts in the position shown in FIG. 2, it will be understood that the drill rod 8, outer barrel 2, and core bit 4 can be rotated in contact with the formation to be sampled, the core, as formed, passing into the inner barrel of the core inner barrel assembly. During this operation, the core barrel will remain stationary, so far as rotation and upward movement are concerned.

The overshot or retrieving mechanism by which the inner-core-barrel assembly is withdrawn is best seen from FIGS. 2 and 7 and cross-sectional views 3 and 4. FIG. 2 shows this mechanism ready for lowering into retrieving position, while FIG. 7 shows it in lowered position, ready to withdraw the inner-barrel assembly.

This overshot or retrieving mechanism comprises a tubular member 48, into the upper end of which is screwed a plug 50. The bore of tubular member 48 throughout a portion of its length is tapered, as seen at 52, for the reception of a locking cone 54. Removably secured to the lower end of the overshot tube 48 is overshot foot 56. The locking cone 54 is spring-loaded by spring 58.

The locking cone 54 is provided with an axial throughbore 60, and the removable overshot foot 56 is provided with an axial through-bore 62, the bores 60 and 62 being aligned with each other and with the head pin 34 of the inner core barrel assembly.

The overshot tube 48 is provided with a cam slot 64, and the locking cone 54 carries a cooperating locking pin 66, which extends radially of the locking cone into the cam slot 64-.

The locking cone 54 adjacent its'lower or inner end is drilled circumferentially for the reception of locking balls 68, which, with the parts assembled, ride along the tapered bore of the overshot tube 48.

7t designates a spindle in axial alignment with the plug 50 of the overshot and attached at its lower end to the plug by a shear pin '72. Slidably mounted on this spindle are jar members 74, 76, and 78, which may be thread-coupled, as shown. The jar member 76 of this group is tubular, and the head of the spindle 70 lies Within this member. Extending into the upper jar member 78 and secured thereto in any convenient fashion is a cable 80, by which the driller may raise and lower the overshot and inner-barrel assembly.

In the operation of the improved core-taking apparatus, the drill bit 8 will initially rest at the bottom of the hole being drilled, and the sectional drill rod 4 attached to the outer barrel will extend to the surface of the earth, where conventional equipment will, of course, be provided for rotating and advancing the drill rod and bit. If drilling fluid or mud, introduced into the drill rod, remains in the hole, the inner-core-barrel assembly may be dropped by gravity into position, the drilling fluid satisfactorily controlling the rate of fall, and the assembly finally taking the position shown in FIG. 2.

In its descent, the inner-barrel assembly will spread the latch fingers 36 outwardly, as permitted by the tapered areas 46 of outer-barrel section 38, so that the inner-barrel assembly can continue its downward or inward movement until the shoulder 42 on the exterior of barrel head 26 engages the finger ring or annulus 37. In this final position, the upper or outer end of the barrel head 26 has passed theshoulders 44 of the latch fingers 36, and the fingers will have sprung inwardly to latching position, so that the inner-barrel assembly is latched against outward movement, and, inasmuch as the shoulder 42 on the inner-barrel head 26 is in contact with the finger ring or annulus 37, which carries the latching fingers 36, further inward movement of the innerbarrel assembly is positively prevented. It will be apparent, therefore, that under these conditions the inner barrel assembly is latched against both inward and outward dis placement. r

In retrieving or raising the inner barrel of the core barrel assembly tothe surface, the driller simply lowers theovershot or retrieving mechanism into the outer barrel. A-s'this assembly descends, the head of the pin 34, which is rigidly mounted in the upper or outer end of the barrel head 26 of the inner barrel, will enter the throughbores 62 and-60 of the overshot foot 56 and locking cone 54, respectively. In this operation, the locking cone 54 will be forced upwardly against the actionof its loading spring 58, and the locking pin 66 of the locking cone willhave moved part way along the cam slot 64 toward the outer extremity of the slot. By the time the overshot has descended to the position shown in FIG. 7, the overshot foot 56 will have spread the fingers 36 outwardly to' unlatched' position, so that the inner-core-barrel assembly is now no longer latched but is free to be'lifted 4. out of the outer barrel and drill rod. As the driller raises the cable 86) by which the overshot is suspended,

the locking balls 63, which "at this moment are below the enlarged head of the inner-barrel pin 34, will roll down the tapered surface of overshot tube 43, thereby locking the overshot or retrieving mechanism to the innercore-barrel assembly, and the latter can now be lifted out of the outer-barrel assembly and drill rod.

As will be seen from FIGS. 2 and 7, for example, the outer end of earn slot 64 is provided with alocking recess 82 for receiving the pin 66 under certain conditions, to lock the locking cone 54 in retracted position. To prevent the pin 66 under usual conditions from being moved into this locking recess, a key 84 is secured to the removable foot 56 of the retrieving mechanism and extends upwardly along a groove 86 in the tubular member 48 of the retrieving mechanism and across the cam slot 64. This key is more or less a precautionary measure and is not necessarily essential. For example, if the retrieving mechanism were lowered too fast, the resisttance of the drilling fluid in the hole might force the looking cone 54, balls 68, and pin 66 outwardly far enough for the pin to drop into the locking recess, so that the cone would be locked and could not drop down into position where the balls 68 could move beneath the enlarged head of the pin 34 to lock the retrieving mechanism to the inner core barrel.

As above pointed out, when drilling fluid remains in the hole, the inner-barrel assembly may be allowed to drop by gravity into position in the outer barrel. There are cases, however, when drilling with a fluid, such as mud or water, where the drilling fluid is not returned to the surface but is lost through caverns or fissures in the formation being sampled. This means that, although 'w'atermay be pumped into the hole and used for drilling, when the pump is shut off and the retrieving procedure started, the water in the hole will escape. This is a dry hole, and a different procedure must be followed in lowering the inner barrel into position.

In working with a dry hole, the retrieving mechanism is attached, above ground, to the inner-barrel assembly and the assembly lowered into position. The retrieving mechanism is then disengaged from the inner-barrel assembly and lifted to the surface.

With reference to this aspect of the invention, the foot 56 of the overshot or retrieving mechanism is removed, including the key 84. The inner-barrel assembly and overshot are then coupled to each other by dropping the overshot over the inner-barrel assembly until the parts are as shown in FIG. 8. The inner barrel and overshot may now be lowered through the drill rod and outer barrel, the locking balls 68 holding the overshot and inner barrel coupled together. By the time the inner-barrel assembly has been brought to rest by engagement of the shoulder '42 of the inner barrel with the annulus carrying the latch -fingers-36, the fingers will have sprung over the end of the inner-barrel head 26, so that the inner barrel is now latched in position.

The parts will now have assumed the positions shown in FIG. 9, from which it will be seen that the shoulder 85 on the pin 34- has engaged the end of the locking cone 54, raising the cone sufliciently for the balls 68 to move away from the pin 34- and the pin 66, which is carried by the cone, to have. been moved along the cam slot 64 into position above the locking recess 82.

7 As the overshot is rased to withdraw it from the drill red, the pin 66 will drop into recess 82 to hold the cone 54 against downward movement, as viewed in FIG. 9, effectively preventing relocking of the overshot to the core assembly and permitting the overshot to be withdrawn by itself, leaving the core barrel assembly in place in the hole. It will be appreciated, of course, that, when the core barrel assembly and core are to be retrieved, the removable foot 56 of the overshot is replaced, and the a users procedure followed as described in connection with FIGS. 1 to 7.

It will be seen from all of the foregoing that new and novel mechanism has been provided in connection with rotary core-drilling apparatus wherein the inner barrel of the core barrel assembly along with the core sample can be brought to the surface without disturbing the outer barrel of the core barrel assembly as well as the drill rod.

It will be seen furthermore that the inner barrelof the assembly is locked in position within the outer barrel again-st axial movement either" direction, thereby maintaining the proper relation between the inner end of the inner barrel and the core bit carried by the outer barrel for the desired flow of drilling'fiuid, while preventing lifting of the inner barrel relative to the outer barrel and bit as drilling proceeds.

It will be seen also that provision has been made to enable the outeubarrel assembly and drill rod to be rotated in conventional fashion without, however, imparting rotation to that part of the inner-barrel assembly which receives the core sample, thereby protecting the core against damage.

It will be seen furthermore that the inner barrel of the core barrel assembly can be positioned with equal facility in a wet hole or a so-called dry hole.

As will be seen from the drawings, ample provisionhas been made for forcing drilling fluid through the equipment while drilling is proceeding. The inner-barrel head 26 is provided with bores 90 for fluid, which can then flow down the annular space between the inner and outer barrels, and through the space between the bit 8 and lifter case 10 and across the bit cutting face and thence upwardly in the annular space between the bit and the drilled hole until it returns to the surface. The section 16 of the inner-barrel assembly is provided with a port 92 through the wall thereof. This port has a double function in that it allows water to flow around the core as drilling advances, and it also permits of the escape of entrapped air from within the inner-barrel assembly, thereby facilitating lowering of the inner barrel of the core barrel assembly within the outer barrel.

It is to be understood that changes may be made in the details of construction and arrangement of parts shown and described within the purview of this invention.

What we claim is: a

1. Core-taking apparatus comprising, in combination, an elongated outer core barrel divided transversely into sections, said barrel being rotatable on its major axis; a core bit secured to the inner end of said barrel and rotatable with the barrel; an elongated, non-rotatable inner core barrel insertable into and withdrawable from said outer barrel; stop means on the wall of the outer barrel and engageable by the inner barrel positively to limit the extent of inward movement of the inner barrel; and spring-metal latch fingers within the outer barrel and clamped between adjacent sections thereof, said fingers extending along the inside of the outer barrel and so positioned as to be engaged by theiinner barrel and deflected outwardly away from each other throughout inward movement of the inner barrel, and so positioned with respect to the said stop means that when the inner barrel has engaged the stop means the outer end of the barrel will have passed the outer ends of said fingers, and the fingers will spring inwardly to their initial position to overlie and engage the outer end of the inner barrel to retain it against withdrawal.

2. Core-taking apparatus comprising, in combination, an elongated outer core barrel divided transversely into sections or lengths, said barrel being rotatable on its major axis; a core bit secured to the inner end of said barrel and rotatable therewith; an elongated inner core barrel insertable into and withdrawable from said outer barrel, said inner barrel being divided transversely into two sections intermediate its ends; an antifriction bearing between the twosections; an annulus within the outer barrel clamped between adjacent sections of said barrel; latch fingers of spring metal integral with said annulus and extending along the inner wall of the outer barrel; a shoulder on the periphery of the inner barrel adapted to engage said annulus,,thereby to limit inward movement of the inner barrel, said fingers being so positioned as to be deflected outwardly by the inner barrel throughout the inward movement of theinner barrel, said fingers springing back to initialposition when the inner barrel has moved inwardly of the outer barrel sufficiently to engage said annulus so as to overhang the head of said inner barrel and latch the inner barrel in engagement with said stop means, said inner barrel engaging the stop means above said antifriction bearing, whereby the section of the inner barrel below said bearing will remain stationary during rotation of the outerbarrel.

3. Core-taking apparatus comprising, in combination, a rotatable outer core barrel; a core bit secured to the inner end of said barrel and rotatable therewith; an inner core barrel within said outer core barrel for receiving core from said bit as the core is being formed; barrellatching fingers secured to the wall of said outer barrel and engaging the inner barrel when the latter is in corereceiving position, to latch the inner barrel against outward movement during core-taking; retrieving mechanism for the inner core barrel adapted to be lowered into the outer barrel to brin the inner end of the retrieving mechanism into engagement with said latching fingers to move the same out of latched position, said retrieving mechanism comprising a sleeve having an inwardly tapered axial bore, a spring-loaded locking cone slidable in the tapered bore of said sleeve, said cone having a straights ded axial bore, the wall of said cone being provided with openings therethrough disposed circumferentially thereof, and coupling or locking balls loosely disposed in said openings; and a shouldered, outwardly tapered pin projecting upwardly from the head of said inner barrel in position to enter the axial bore of the locking cone and contact said locking balls upon the said inward movement of the retrieving mechanism into unlatching contact with said fingers and into contact with the shoulder on said pin, thereby to push the locking cone outwardly of the outer barrel against the action of its spring, said spring upon subsequent shift outward movement of the retrieving mechanism efiecting inward movement of the locking cone to couple lock the retrieving mechanism to the said pin through said balls While maintaining the fingers unlatched, whereby the inner barrel and the retrieving mechanism may be withdrawn as a unit from the outer core barrel.

4. Core-taking apparatus comprising, in combination, a rotatable outer core barrel; a bit carried by and rotatable with said barrel; an inner core barrel for receiving the core from said bit, said inner barrel being insertable into and withdrawable from said outer barrel; a stop for limiting the inward movement of said inner barrel; mechanism adapted to be coupled to the inner barrel for lowering the inner barrel into the outer barrel, said mechanism comprising a sleeve having an inwardly tapered axial bore, a spring-loaded locking cone within said tapered bore and slidable therein, said cone having a straight-sided axial bore, radial bores through the wall of the bore of said cone, and a locking ball loosely mounted in each of said radial bores; an outwardly tapered pin, projecting from the outer end or head of the inner barrel, adapted, when the mechanism is being coupled to the inner barrel, to enter the axial bore in said locking cone and engage said locking balls to push the cone outwardly of said sleeve until the cone has been moved sufficiently for the outer end of the pin to pass the balls, to allow the cone-spring to restore the cone to initial position, thereby to couple the mechanism to the pin for lowering the inner barrel into the outer barrel; a shoulder at the base of the tapered portion of the said tapered pin adapted to be engaged by the inner end of said cone as the inner barrel, in its movement into the outer barrel, engages the stop means for the barrel, said shoulder preventing any further inward movement of the cone while leaving said sleeve free to continue its inward movement until it engages the outer end of the inner barrel, thereby to uncouple the mechanism from the barrel; a pin secured to the wall of said cone and projecting radially thereof toward the said sleeve; a cam'slot in the sleeve for receiving said pin; and a pin-locking recess at the other extremity of said slot, said movement of the said sleeve subsequent to the said engagement of the cone with said shoulder moving the said cam slot to a position where the pin is directly over the said locking recess, whereby outward movement of the sleeve will cause the pin to engage said locking recess to maintain the mechanism and inner barrel uncoupled, to enable the said mechanism to be Withdrawn from the inner barrel.

5. Core-taking apparatus comprising, in combination, an elongated outer core barrel rotatable on its major axis; a core bit secured to the inner end of said barrel and rotatable therewith; an inner, non-rotatable core barrel axially insertable into and withdrawable from the outer core barrel; stop means positively to limit the inward movement of the inner barrel; latch fingers of spring metal, provided at their outer ends with latching shoulders, secured to the wall of the outer barrel, the inner barrel engaging and spreading said fingers throughout its inward movement until the inner barrel engages said stop means, the fingers then springing back to their initial position to engage the latching shoulders with the outer end of the head of the inner barrel, therebyto latch the inner barrel against the stop means and against outward movement relative to the outer barrel; mechanism for retrieving the inner barrel, said mechanism being insertable into the outer barrel into spreading engagement with said latch fingers to spread and hold the same out of latching position with respect to the inner barrel; and means forming part of the retrieving mechanism and actuated by outward movement of the retrieving mechanism to lock the retrieving mechanism to the inner core barrel while maintaining the said fingers in unlatched position, whereby the inner core'barrel and retrieving mechanism are rendered withdrawable as a unit from within the outer core barrel, said locking means comprising a locking cone forming part of the retrieving mechanism, a tapered pin carried by the head of the inner barrel and adapted to be received by said cone, and locking balls carried by said cone adapted to engage said pin to lock the cone to the pin. V

References Cited in the file of this patent UNITED STATES PATENTS Pickardet al. Apr. 8, 

